Gas control valve in water heater

Abstract

A gas control valve in a water heater is provided for improving the ease of assembling, minimizing the size and the cost, and decreasing the limitation of layout design. For example, in a flame-retention, storage type closed vessel gas water heater for automatically controlling the temperature of hot water in a tank to a predetermined temperature, a cam member 3 having a pilot cam surface 3 b, a main cam surface 3 a, and an extinction cam surface 3 c thereof arranged along one track is fixedly mounted on an ignition operating shaft 2 equipped with an ignition knob 1 for turning together and also arranged for direct engagement with the proximal end 13 a of the valve pin 13 which has a pilot valve V 1 fixedly mounted on the distal end thereof, a main valve V slidably mounted thereon below the pilot valve V 1, and a main valve opening collar plate 14 fixedly mounted thereon below the main valve V as spaced by a given distance “a” from the same so that the valve pin 13 can be shifted forward and backward by a predetermined sequence of actions of the cam member 3 to open and close the pilot valve V 1 and the main valve V aligned along the axis of the valve pin 13 in response to the movement of the ignition knob 1 for controlling the supply of fuel gas to turn on and off the combustion of the water heater.

What is claimed is:  
     
       1. A gas control valve in a water heater comprising a pilot valve and a main valve aligned along one axis and arranged operable with an ignition knob for opening and closing the pilot valve and the main valve, wherein the pilot valve and the main valve are opened in this order and closed in reverse order. 
     
     
       2. A gas control valve in a water heater according to  claim 1 , further comprising: 
       a cam member mounted on an operating shaft provided with the ignition knob and having a pilot cam surface, a main cam surface, and an extinction cam surface thereof aligned in one track; and  
       a valve pin having the pilot valve fixedly mounted on the distal end thereof, the main valve slidably mounted thereon below the pilot valve, and a main valve opening collar plate fixedly mounted thereon below the main valve as spaced by a given distance from the main valve, and arranged for engagement at the proximal end with the cam member, wherein  
       the valve pin is moved forward and backward by the action of the cam member determined by a program so that the pilot valve and the main valve, aligned along the axis of the valve pin, can be opened in this order and closed in reverse order in response to the movement of the ignition knob for turning on and off a combusting action.